The Cinereous Harrier is distributed along the Andes from Colombia southwards and throughout most of Argentina with some migration into Paraguay, Uruguay and southern Brazil. Belton suggests that it is relatively uncommon in Rio Grande do Sul as it appears to be in much of its range.

It is smaller and more compact than Long-winged HarrierC. buffoni and its flight appeared to be much more rapid.

In flight from below the male's wings are mostly white with contrasting black primaries and a dark trailing edge on the secondaries. The body is barred rufous and the rump is white.

It is found in open country including agricultural land where it hunts for small mammals, birds and reptiles as well as insects and frogs.